Kazuhiro Nara

Antioxidative Activity of Bound-Form Phenolics in Potato Peel

Free and bound-form phenolics were isolated from potato (cv. Toyoshiro) flesh and peel. The free and bound-form phenolics in the peel showed high DPPH radical scavenging activity, while those in the flesh showed low activity. The total amount of chlorogenic acid and caffeic acid in the free-form phenolics from the peel was highly correlated with the DPPH radical scavenging activity. Ferulic acid was identified as the active radical scavenging compound in the bound-form phenolics from the peel. The potato peel may therefore offer an effective source of an antioxidative.

Antioxidative activity of water soluble polysaccharide in pumpkin fruits (Cucurbita maxima Duchesne).

We evaluated the antioxidative activity of a water soluble polysaccharide fraction (WSP) from pumpkin fruits (Cucurbita maxima Duchesne). In the WSP, DPPH radical scavenging and superoxide dismutase-like activity increased depending on the total sugar content. Furthermore, the WSP can serve as an inhibitor of ascorbic acid oxidation. The efficacy was also affected by the total sugar content.

Germplasm Release: Saikai 35, a Male and Female Fertile Breeding Line Carrying Solanum Phureja-Derived Cytoplasm and Potato Cyst Nematode Resistance (H1) and Potato Virus Y Resistance (Rychc) Genes

Saikai 35 was bred from a cross between TD0101 as the female, which was created by chromosome-doubling of a good-tasting and bacterial wilt resistant diploid variety, Inca-no-mezame, and Sakurafubuki as the male, the latter of which has H1 and Rychc genes showing resistance to potato cyst nematode (PCN) and Potato virus Y (PVY), respectively. All favorable traits were combined into Saikai 35, although marketable yield in the spring cropping was 20.4–21.0% lower than those of major double-cropping varieties. Saikai 35 is particularly useful for having Solanum phureja-derived cytoplasm (S/ε), which resulted in high male and female fertility. In addition, sets of very tightly linked DNA markers sandwiching H1 and Rychc are available. Therefore, Saikai 35 is being released as a breeding line, which can confer efficiently PCN and PVY resistance genes.ResumenSaikai 35 es el resultado de la cruza entre TD0101 como hembra, que se creó por duplicidad de cromosomas de una variedad diploide de buen sabor y resistente a la marchitez bacteriana, Inca-no-mezame, y Sakurafubuki como macho, que tiene genes de H1 y Rychc que muestran resistencia al nematodo de quiste de la papa (PCN) y al virus Y de la papa (PVY), respectivamente. Se combinaron todos los caracteres favorables en Saikai 35, aunque el rendimiento comercial en el cultivo de primavera fue 20.4–21.0% más bajo que las principales variedades de doble cultivo. Saikai es particularmente útil por tener citoplasma derivado de Solanum phureja (S/ε), que da como resultado alta fertilidad masculina y femenina. Además, están disponibles juegos de marcadores de DNA fuertemente ligados en sándwich con H1 y Rychc. De aquí que Saikai 35 se está liberando como una línea de mejoramiento, que puede conferir eficientemente genes de resistencia a PCN y PVY.

Evaluation of biological activities of a groundnut (Apios americana Medik) extract containing a novel isoflavone

Groundnut (Apios americana Medik) contains a novel isoflavone, genistein-7-O-gentiobioside. In the present study, we examined the biological activities of an alcohol extract of groundnut containing genistein-7-O-gentiobioside as the main component. Although the groundnut extract by itself did not show antioxidative activity, it drove the antioxidative system in cells. Pretreatment of human breast carcinoma MCF-7 cells for 24 h with the groundnut extract and soybean isoflavone increased gene expression of heme oxygenase-1 (HO-1), a major antioxidative stress enzyme. These groundnut extract-treated cells showed antioxidative activity against free radicals derived from a radical initiator. Pretreatment of cells with 100 μg/mL groundnut extract prevented the depletion of glutathione by the radical initiator; however, treatment with 100 μg/mL of soybean isoflavone injured the cell membrane, indicating that glutathione might be released to the extracellular environment. These results suggest that the groundnut extract had isoflavone-like activity. Like soybean, groundnuts are a good source of isoflavones.

Breeding of a new potato variety ‘Nagasaki Kogane’ with high eating quality, high carotenoid content, and resistance to diseases and pests

‘Nagasaki Kogane’ is a new potato variety bred from a cross between ‘Saikai 35’ as a female parent and ‘Saikai 33’ as a male. ‘Saikai 35’ is resistant to bacterial wilt, contains the H1 and Rychc genes for resistance to the potato cyst nematode (PCN) and potato virus Y (PVY), respectively, and has high carotenoid content, while ‘Saikai 33’ has large and high-yielding tubers and is resistant to both bacterial wilt and PCN. The carotenoid content of ‘Nagasaki Kogane’ is higher than that of ‘Dejima’, a common double cropping variety. The taste quality of steamed ‘Nagasaki Kogane’ is comparable to that of ‘Inca-no-mezame’ tubers, which has high levels of carotenoid, and superior to ‘Nishiyutaka’, another popular double cropping variety. ‘Nagasaki Kogane’ is suitable for French fries, because its tuber has high starch content. The marketable yield of ‘Nagasaki Kogane’ was higher than that of ‘Inca-no-mezame’ in spring cropping, although it was lower than that of ‘Nishiyutaka’ in double cropping regions. ‘Nagasaki Kogane’ tubers are larger on average than ‘Inca-no-mezame’ tubers in spring cropping. Moreover, the ‘Nagasaki Kogane’ variety is resistant to PCN and PVY, and exhibits a high level of resistance to bacterial wilt.

Influence of Culture Medium on the Composition of Water-soluble Polysaccharides in Ganoderma lucidum Fruit Body

各種剪定材（カキ，クワ，サクラ，ウメ，ナラ，ブドウおよびリンゴ）を菌床に用いて栽培した鹿角霊芝子実体の水抽出物の差異について検討した．子実体から抽出した水溶性画分（WS）は，菌床の違いで収量（全糖量）が異なり，WSから得られた水溶性多糖画分（WS-H）でも収量に差異が認められた．WS-Hの全糖量はカキで最も多く，次いでリンゴとクワが多かった．構成糖組成の比較を行ったところ，カキおよびクワではアラビノースおよびキシロースが顕著に多く見られた．他のものではガラクトース，マンノースおよびグルコースが多く含まれていた．糖結合様式について検討したところ，ガラクタン系多糖およびグルカン系多糖で構成されていた．一方，カキおよびクワではガラクタン系多糖の他に，キシラン系多糖も多く含まれていた．したがって，異なる剪定材を菌床に用いて栽培した鹿角霊芝の子実体より抽出した水溶性多糖には違いがあることがわかった．今回の結果から，菌床を変えることで，異なる効能を備えた鹿角霊芝子実体の栽培が期待できるとともに，本来廃棄物として処理されている剪定材を有効に利用する可能性が示唆された．